ZestCalc.com
Appearance
Language

Greatest Common Factor Calculator

Calculate the Greatest Common Factor (GCF) of two or more numbers with step-by-step solutions.

Greatest Common Factor Calculator

Find the GCF of multiple numbers

What is the Greatest Common Factor?

The Greatest Common Factor (GCF), also known as the Greatest Common Divisor (GCD), is the largest positive integer that divides two or more numbers without leaving a remainder. It is most commonly used to simplify fractions.

How to Calculate

To find the GCF, list the prime factors of each number. The GCF is the product of the common prime factors. Example: GCF(12, 18) • 12 = 2 × 2 × 3 • 18 = 2 × 3 × 3 Common factors are 2 and 3. So, GCF is 2 × 3 = 6.

GCF(a,b)=product of common prime factors\text{GCF}(a, b) = \text{product of common prime factors}

Quick Examples

GCF(12,18)=6\text{GCF}(12, 18) = 6
GCF(24,36)=12\text{GCF}(24, 36) = 12
GCF(15,25,30)=5\text{GCF}(15, 25, 30) = 5
GCF(7,13)=1\text{GCF}(7, 13) = 1

Tips for Finding the GCF

  • The GCF cannot be larger than the smallest number in your set.
  • If the smaller number divides the larger number evenly, the smaller number is the GCF.
  • If the numbers have no common factors other than 1 (they are coprime), their GCF is 1.
  • The GCF of any number and 1 is always 1.